242 Biograpldcal Memoir of the late Dr Turner. 



nufactories in question. The results proving of interest, as well 

 in a scientific as in a practical point of view, we extended our 

 researches to the gases in general, and arrived at the following 

 conclusions : — viz. That, as in regard to animal life, so also in 

 respect to vegetable life, there are two great classes of gaseous 

 poisons, one comprising the irritant gases and vapours, which 

 injure and destroy vegetables by attacking their external parts 

 or local organs, the other comprising the narcotic gases, whicli 

 assail vegetable life at its centre and throughout the whole orga- 

 nization of the plant : — that from the former poisons plants may 

 recover with partial local Injuries, if they are removed in time 

 into fresh air, while the latter prove inevitably fatal if the slight- 

 est sign of their narcotic action be once developed : — And that 

 some of the irritant gases, such as sulphurous and muriatic acid, 

 are so intensely energetic, that in the course of two days the 

 whole vegetation of various species of plants will be destroyed 

 by the most minute quantities, diluted to so great an extent as 

 to be wholly inappreciable by any of the animal senses. These 

 experiments have, I believe, been considered decisive of the ge- 

 neral question ; and on two subsequent occasions on which I 

 have been consulted as to the question of damage by the same 

 kind of works, I have been able to trace the identical effects on 

 the great scale which my friend and I witnessed in our re- 

 searches. In one instance the devastation committed was enor- 

 mous, vegetation being for the most part miserably stunted, or 

 blasted altogether, to a distance of fully a third of a mile from 

 the works in the prevailing direction of the wind. 



But the year 1827 was marked by two steps of far greater 

 consequence than any yet mentioned : for towards the beginning 

 of it he brought out the first edition of his Elements of Che- 

 mistry ; and towards the close he was nominated Chemical Pro- 

 fessor in the University College, London. 



Dr Turner, as I have reason to remember, entered on the 

 laborious task of preparing an Elementary work on Chemistry, 

 with the modesty and diffidence which characterized his whole 

 conduct, and which may perfectly characterize the conduct of 

 such a man, without in the least degree taking away from its 

 energy or success. He derived great encouragement, however, 

 from the welcome reception met with a short time previously by 



